Developmental Dysplasia of the Hip

What is Developmental Dysplasia of the Hip (DDH)?

Developmental dysplasia of the hip (DDH) is a term used to describe a wide range of hip abnormalities ranging from a misshapen ball or socket to a complete dislocation of the hip. DDH happens in one in every 1,000 births and can sometimes develop after birth. DDH is most common in first-born breech females who also have a close relative with the condition. With DDH, the hip socket (acetabulum) may be shallow. This can allow the ball (femoral head) of the leg bone to slip in and out of the hip socket. The ball may move partially or completely out of the socket. Treatment options vary based on your child's age.

What causes DDH?

DDH is usually caused by genetic and environmental factors. DDH is more common in females. One of the environmental factors may be the baby's response to the mother's hormones during pregnancy. A tight uterus that limits fetal movement or a breech position are also associated with DDH. DDH is more likely to occur in the left hip.

What are the risk factors for DDH?

First-born babies are at higher risk because the uterus is small and there is limited room for the baby to move, affecting the development of the hip. Other risk factors may include:

Family history of DDH, or very flexible ligaments

Position of the baby in the uterus, especially with breech presentations

Associations with other orthopaedic problems that include metatarsus adductus, clubfoot deformity, congenital conditions and other syndromes

Symptoms and Treatments

What are the signs or symptoms of DDH?

Signs of DDH in babies, infants and toddlers include:

Leg may appear shorter on the side of the affected hip.

The rotation of the affected hip may be different.

Folds in the skin of the thigh or buttocks may appear uneven.

Space between the legs may look wider than normal.

The hip may shift, click or clunk during certain movements, such as diaper changes.

Signs of DDH in adolescents, teens and young adults include:

Hip pain

Clicking sound in the hip joint

Catching feeling in hip joint

Limited or excessive movement of the hip

Difference in limb length

How is DDH diagnosed?

Your doctor will do a physical exam of your child at birth and during infancy to check for DDH and other hip problems. Signs may not show until later in life. Diagnostic procedures may include:

Ultrasound (sonography)--uses high-frequency sound waves and a computer to create images of blood vessels, tissues and organs. Ultrasounds are used to assess the shape and stability of the hip.

Computed tomography (CT) scan--uses a combination of X-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat and organs. CT scans are more detailed than general X-rays.

Magnetic resonance imaging (MRI)--uses a combination of large magnets, radiofrequencies and a computer to produce detailed images of organs and structures within the body.

What can be done?

The goal of treatment is to reposition the ball back into the hip socket so the hip can stabilize and then develop normally. Some hips do not continue to develop normally after they stabilize. Further treatment may become necessary.

Treatment is based your child's:

Age, health and medical history

Extent of the DDH

Tolerance for medicine, procedures or therapies

Treatment for babies and infants

Pavlik harness--is typically used on babies up to age 6 months to guide the hip into place, while allowing some movement of the legs. The harness is applied by your baby's doctor and is usually worn full time for at least six weeks. Your baby is seen often during this time so that the harness may be checked for proper fit and to examine the hip. During treatment, ultrasounds or X-rays may be used to check the position of the hip and assess progress. Treatment typically ends when X-ray or ultrasound evaluations are normal. DDH may be successfully treated with the Pavlik harness in infancy, but it is important to monitor the hips during growth. Sometimes the hip may fail to fully develop and further treatment may be necessary.

Treatment for toddlers

Closed reduction surgery and casting--If the other methods are not successful, or if DDH is diagnosed after the age of 6 months, a closed reduction surgery may be required to put the hip back into place manually. This surgery is often combined with other procedures, such as arthrogram and adductor tenotomy, to help assess the reduction and increase the hip stability. With an arthrogram, X-rays are taken after injecting contrast into the joint to highlight the cartilage and other soft tissues that are not seen with X-rays alone. An adductor tenotomy involves cutting tendons to increase hip flexibility. If closed reduction surgery is successful, a special cast (spica cast) is used to hold the hip in place. The spica cast is worn for three to six months. The cast is changed from time to time to accommodate your child's growth. Your child may need to wear a brace after the cast is removed. Physical therapy may be needed to help make the muscles around the hip stronger.

Treatment for adolescents, teens and young adults

Periacetabular Osteotomy (PAO)--Older children at or near skeletal maturity may benefit from a periacetabular osteotomy (PAO). With a PAO, cuts are made around the hip socket. This allows the hip socket to be moved into a more normal position. This reduces joint stress and improves hip function. A PAO may also delay or eliminate the need for total hip replacement later in life. Some patients may need physical therapy for a full recovery.

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6 related images

What are X-rays?

X-rays are made by using low levels of external radiation to produce images of the body, the organs, and other internal structures for diagnostic purposes. X-rays pass through body structures onto specially treated plates (similar to camera film) and a negative-type picture is made. The more solid a structure is, the whiter it appears on the film. For this reason, bones appear very white on an X-ray film, but less dense tissue such as muscle, blood, skin and fat appears darker. An X-ray provides a picture of inside the body by using special radioactive rays. An X-ray can show bones, tissues or parts of organs.